South Korea's Industrial Heat Pumps Grow Beyond Its Testing Standards

A 600 RT proposal meets a market already using 1,000 RT machines

South Korea's proposed national standard for water source heat pumps would cover equipment with rated heating and cooling capacity up to 2,110 kilowatts, approximately 600 refrigeration tons (RT). Yet the Korea World Trade Center has already installed a 1,000 RT class system, described as the country's first water source heat pump of that size. Equipment at or above 1,000 RT is also entering industries including paper manufacturing.

The proposal from the Korean Agency for Technology and Standards would expand the existing coverage of approximately 150 RT fourfold. It would still stop well below the capacity of machines now being installed. A 1,000 RT unit is about 67% larger than the proposed 600 RT ceiling, leaving a substantial gap between the standard's scope and actual purchasing decisions.

That mismatch matters as the government promotes heat pumps for cleaner industrial heat and large buildings under its K-GX green transition initiative. Buyers need comparable evidence of efficiency and electricity consumption before committing to equipment, power infrastructure and construction work. Without a common testing framework for these larger machines, those decisions become harder to verify.

The problem has a documented history. A research program launched in October 2020 aimed to develop a 500 RT water source heat pump alongside technical standards and a certification system. A September 2022 account of that program identified the absence of performance testing criteria above 530 kilowatts, approximately 150 RT, as a barrier to using certified large equipment.

The newer proposal would move that boundary substantially. The central issue is whether its 600 RT limit can serve a market that has already moved beyond the scale targeted by the earlier research.

What the capacity figures actually mean

A refrigeration ton measures thermal capacity, not the weight of the equipment. The figures used in the proposed standard, 2,110 kilowatts and approximately 600 RT, describe how much heating or cooling a machine can deliver. They do not mean that the machine draws 2,110 kilowatts of electricity.

That distinction is essential for industrial buyers. A heat pump uses electricity to move heat rather than producing all its useful heat directly from electrical resistance. Its electrical demand depends on efficiency and operating conditions, including the temperature of the source water and the temperature required by the building or industrial process.

Two machines with the same rated thermal capacity can therefore have different electricity requirements. Comparing them fairly requires equivalent testing conditions and a clear definition of which equipment is included in the measurement. A capacity rating alone cannot establish the electricity supply a site will need.

The proposed standard concerns systems that exchange heat between a water source and a water circuit serving the building or process. It does not, by itself, resolve the separate standards gap identified for large industrial air source heat pumps. Those machines draw heat from air and need testing suited to their own operating conditions.

How the certification gap developed

In 2022, water source heat pumps did not have dedicated certification criteria. Instead, installation criteria used standards developed for ground source heat pumps, which exchange heat with the ground. The relevant standards were KS B 8292, KS B 8293 and KS B 8294.

Their scope differed by equipment type. KS B 8292 covered systems transferring heat between water circuits up to 530 kilowatts. KS B 8293 covered systems transferring heat between water and air up to 175 kilowatts, while KS B 8294 covered multiple unit water and air systems up to the same 175 kilowatt limit.

Those distinctions prevent a simple reading of 150 RT as the limit for every heat pump category. Approximately 150 RT was the boundary relevant to the water circuit equipment discussed in the large water source research program. Other categories had smaller limits.

The reported absence of testing criteria above that boundary made certified large equipment effectively unavailable through the framework described in 2022. It did not mean that larger machines could not be manufactured or installed. The subsequent 1,000 RT installation demonstrates the difference between technical deployment and coverage under a common domestic certification system.

A research program built around 500 RT

The earlier development effort was led by Korea Water Resources Corporation, with support from the Ministry of Trade, Industry and Energy and the Korea Institute of Energy Technology Evaluation and Planning. Eleven organizations participated, including the Korea Institute of Energy Research and the Korea Refrigeration and Air Conditioning Assessment Center.

The program was scheduled to run for 39 months, from October 2020 through December 2023. Its objectives included river water heat exchange technology, a large heat pump using refrigerants with a lower environmental impact, systems combining thermal storage with heating and cooling, and technical standards and certification for large equipment.

The intended 500 RT machine reflected expectations at the time about demand during the early expansion of water source heating and cooling. The latest criticism of the 600 RT proposal is that it remains tied to research undertaken four years earlier, while customers are now installing machines twice the size of that original development target.

The sequence shows how the policy and equipment market have moved:

• October 2019: An amendment to the enforcement decree of the Act on the Promotion of the Development, Use and Diffusion of New and Renewable Energy brought river water heat within the renewable energy framework.
• October 2020: The 39 month research program began, including development of a 500 RT heat pump and certification criteria.
• April 2022: The Environment Ministry and Korea Water Resources Corporation signed pilot agreements with eight institutions covering nine buildings.
• September 19, 2022: The research program was described as still underway, with testing criteria above approximately 150 RT identified as a problem.
• December 2023: The program's scheduled completion date.
• The latest standards debate: A proposed ceiling of approximately 600 RT is being challenged because 1,000 RT class installations are already in use.

The Korea World Trade Center installation is described as having occurred in the year before the latest account, but that account's publication date is not specified. Its calendar year cannot be established from that description alone. The scheduled end of the research program also does not establish when its certification objectives were completed or adopted.

Why buyers choose fewer, larger machines

Large heat pumps are attractive for reasons that extend beyond their rated capacity. Using fewer machines can reduce the space needed in a mechanical room and cut the number of water pipes, valves and separate units requiring maintenance. These considerations matter in large buildings where plant space competes with other uses.

The 2022 development program anticipated that many pilot sites would need more than 530 kilowatts of heating or cooling capacity. Meeting those requirements with numerous smaller units was expected to increase installation space and complicate maintenance.

Larger equipment also differs in construction. Smaller heat pumps commonly use reciprocating or scroll compressors. As capacity increases, manufacturers may use screw compressors or centrifugal compressors, which compress refrigerant using a rapidly rotating impeller.

The large water source systems described in the research account use separate heat exchangers for producing hot and cold water. Rather than reversing refrigerant flow to switch between heating and cooling, they select the appropriate water circuit through valves. This allows each heat exchanger to be designed for its specific task.

Applications can include building heating and cooling, data center cooling, refrigerated storage, greenhouse heating, hot water and steam production. These are examples of uses for large heat pumps, not evidence that every application already has a 1,000 RT installation in South Korea. Their different temperature requirements help explain why large machines are often designed and manufactured for a particular customer's needs.

Electricity planning depends on credible performance data

The most immediate consequence of the standards gap is uncertainty in procurement. Buyers need to know whether competing machines deliver the same useful heating or cooling while drawing comparable amounts of electricity. Without consistent test conditions, differences in product specifications may reflect different measurement assumptions as well as differences in equipment performance.

The uncertainty extends to the site's electrical infrastructure. Large installations can require additional power equipment and a review of the infrastructure receiving electricity from the grid. Estimates of electrical demand influence the scale of upgrades and the installation budget.

Thermal capacity cannot substitute for this assessment. A factory selecting a 1,000 RT machine needs information about electrical consumption at the temperatures and loads its process requires. The heat pump's efficiency is also only part of the calculation when water must be transported through an extensive pipe network.

Industry representatives are calling for faster standards updates to support public procurement, demonstration projects and larger private installations. The argument is that common verification should develop alongside equipment demand, allowing purchasers to compare products before they commit to expensive site work.

The reported gap does not prove that existing large machines perform poorly. It identifies a missing basis for standardized comparison. Warnings that this could delay domestic adoption or green industry exports are concerns about the consequences, rather than evidence of quantified delays or lost sales.

Pilot projects show the potential, with limits

The April 2022 pilot agreements brought together eight institutions: Samsung Medical Center, WTC Seoul, Mirae Asset Global Investments, Sangju City, NCSoft, Korea Power Exchange, North Chungcheong Province and the South Gyeongsang Provincial Office of Education. Their projects covered nine buildings.

The support described for participating institutions covered 50% of water source equipment costs, including source water pipes, heat exchangers, internal piping and heat pumps. That breadth matters because the machine is only one element of a functioning installation. Access to suitable water and the cost of bringing it to the building can shape the entire project.

For the nine buildings, annual electricity consumption for heating and cooling was projected to fall from 101.9 gigawatt hours to 65.4 gigawatt hours. The difference is 36.5 gigawatt hours, approximately 35.8% of the original total. Annual greenhouse gas reductions were projected at 19,000 tonnes.

Those figures were forecasts associated with introducing the systems, not verified results from completed operation. They illustrate the expected benefit that helped motivate the pilot program, but they cannot establish savings at every industrial site or the performance of today's 1,000 RT machines.

Location also affects the economics. A 2020 study by senior researcher Jo Hang-mun on expanding water source energy in Seoul identified proximity between a water source and a heat customer as a key condition. Longer distances increase the cost of moving water and building pipes, potentially weakening an otherwise promising project.

What standards alone cannot settle

Water source heat pumps use the relatively stable temperature of water to support heating and cooling. In winter they extract heat from the source; in summer they can transfer heat from a building into it. The research program nevertheless identified several technical issues requiring work, including low river temperatures in winter, debris entering the system, pressure shocks in pipes and environmental effects from discharged water.

Compressor design and refrigerant choice also affect performance. The program identified the need for precise testing equipment, reliable bearings for fast rotating compressors and controls to avoid surge, an unstable condition that can disrupt compressor operation. Extending a standard's capacity range therefore needs suitable testing capability, as well as a revised numerical ceiling.

Installation economics involve separate policy decisions. In 2022, water source energy was described as outside the applicable weighting arrangements for renewable energy certificates (RECs). Funding for initial installation costs, financing support and changes to energy tariffs were also identified as issues. Those descriptions establish the concerns at that time, not their current resolution.

Existing heating equipment may require temperatures that do not match the proposed heat pump's output. Water temperature, flow and environmental conditions must also be assessed at each site. Certification can make equipment performance more comparable, but it cannot guarantee that a particular building or factory is suitable.

The immediate unresolved issue is how South Korea will test and certify equipment beyond the proposed 600 RT boundary, particularly machines at or above 1,000 RT. No confirmed timetable is given for extending that range, and no next consultation deadline or adoption date is specified. The practical challenge is to connect the government's deployment ambitions with verification that covers the machines customers are already buying.

Key Points

• The proposed water source heat pump standard covers rated heating and cooling capacity up to 2,110 kilowatts, approximately 600 RT.
• A 1,000 RT class system has been installed at the Korea World Trade Center, and equipment of that scale is entering paper manufacturing.
• The proposed capacity ceiling is four times the existing approximately 150 RT boundary, but still below current large installations.
• A research program scheduled for October 2020 to December 2023 targeted a 500 RT machine and a certification framework.
• The absence of common criteria complicates efficiency comparisons, procurement and electricity infrastructure planning.
• Nine pilot buildings were projected to save 36.5 gigawatt hours of electricity annually. That projection is not a verified operating result.
• No confirmed date is specified for domestic standards covering equipment beyond the proposed 600 RT limit.